AllocationProfiler: introduce allocation_profiler flag in V8 api.

AllocationProfiler: introduce allocation_profiler flag in V8 api.

Allocation profiler needs to instrument code in stubs, biltins etc.
It is a bit tricky thing due to complex structure of v8 heap.
The simplest solution is to create isolate without snapshot.

So I introduced allocation_profiler flag and corresponding
api methods.

  static bool EnableAllocationProfiler(Isolate* isolate);
  static bool IsAllocationProfilerEnabled(Isolate* isolate);

BUG=

Mixed with patch from issue 43693002 by yurys.
Drive by fix: do not count untracked objects twice.

[alph, 2013-11-05 13:55:20]

https://codereview.chromium.org/59373003/diff/1/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/59373003/diff/1/include/v8.h#newcode4605
include/v8.h:4605: */  static bool IsAllocationProfilerEnabled(Isolate*
isolate);
nit: a new line

https://codereview.chromium.org/59373003/diff/1/src/x64/macro-assembler-x64.cc
File src/x64/macro-assembler-x64.cc (right):

https://codereview.chromium.org/59373003/diff/1/src/x64/macro-assembler-x64.c...
src/x64/macro-assembler-x64.cc:4191: addq(rsp, Immediate(2 * kRegisterSize));
Just curious why it's kRegisterSize here and kPointerSize in the previous chunk?

[danno, 2013-11-05 14:23:26]

NOT LGTM. This feature requires some fundamental design follow-up before any
more patches land related to it, this is a patch of a patch of a patch of a
implementation that needs to be re-thought through at a high-level again. I will
be discussing separately with Yury how to proceed later this afternoon.